$f(x)=x+\frac{1}{x}$ হলে, $f\left(\frac{1}{x}\right)=$ কত ?

$x^{2}+\frac{1}{x^{2}}$

$1+\frac{1}{x^{2}}$

$x+\frac{1}{x}$

$x^{2}+1$